1. Field
The present disclosure relates to a road environment recognizing apparatus that recognizes a projection around a road on the basis of an image captured by a camera mounted in a vehicle.
2. Description of the Related Art
Road environment recognizing apparatuses have been hitherto known, which recognize projections around roads from images of the roads in front of vehicles, which are captured by in-vehicle cameras (for example, refer to Japanese Patent Application No. 5195377 and Japanese Patent Application No. 5152002).
Japanese Patent Application No. 5195377 describes a traffic lane boundary detecting apparatus that recognizes road studs for each pixel group of pixels on one horizontal line in an image of a travelling road, which is captured by an image capturing unit, on the basis of the continuous pixels on the one horizontal line, which have luminances higher than or equal to a predetermined threshold value.
Japanese Patent Application No. 5152002 describes a traffic lane recognizing apparatus that, after converting pixels having edge strengths higher than or equal to a threshold value into white and converting pixels having edge strengths lower than the threshold value into black in an edge image of a captured image, recognizes road studs on the basis of the white areas that have areas higher than or equal to a predetermined value and that have aspect ratios higher than or equal to a predetermined value, among the white areas resulting from omnidirectional expansion using, for example, morphological operations.
However, with the technologies in the related art, the projections may not be detected due to the effect of shades caused by sunlight or the like despite the fact that the projections exist around the road and there is room for further improvement in terms of increase in recognition accuracy of the projections around the road.
For example, in the technology disclosed in Japanese Patent Application No. 5195377, since the number of the pixels having the luminances higher than or equal to the predetermined threshold value is reduced when part of the road studs is shaded due to the sunlight or the like, it may not be possible to extract the continuous pixels on the one horizontal line, which have the luminances higher than or equal to the predetermined threshold value. As a result, the road studs may be not recognized despite the fact that the road studs exist.
In contrast, in the technology disclosed in Japanese Patent Application No. 5152002, the size of the expanded white areas is made smaller than the predetermined value when part of the road studs is shaded due to the sunlight or the like. As a result, the road studs may be not recognized even if the road studs exit in a portion corresponding to the white areas.